path_init(): set nd->inode earlier in cwd-relative case

that allows to kill the recheck of nd->seq on the way out in
this case, and this check on the way out is left only for
absolute pathnames.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 12 insertions, 10 deletions

diff --git a/fs/namei.c b/fs/namei.c
index f89fe5f7eac3..a08018b1485c 100644
--- a/fs/namei.c
+++ b/fs/namei.c
@@ -2028,6 +2028,15 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
                         path_get(&nd->root);
                         nd->path = nd->root;
                 }
+                nd->inode = nd->path.dentry->d_inode;
+                if (!(flags & LOOKUP_RCU))
+                        return s;
+                if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
+                        return s;
+                if (!(nd->flags & LOOKUP_ROOT))
+                        nd->root.mnt = NULL;
+                rcu_read_unlock();
+                return ERR_PTR(-ECHILD);
         } else if (nd->dfd == AT_FDCWD) {
                 if (flags & LOOKUP_RCU) {
                         struct fs_struct *fs = current->fs;
@@ -2038,11 +2047,14 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
                         do {
                                 seq = read_seqcount_begin(&fs->seq);
                                 nd->path = fs->pwd;
+                                nd->inode = nd->path.dentry->d_inode;
                                 nd->seq = __read_seqcount_begin(&nd->path.dentry->d_seq);
                         } while (read_seqcount_retry(&fs->seq, seq));
                 } else {
                         get_fs_pwd(current->fs, &nd->path);
+                        nd->inode = nd->path.dentry->d_inode;
                 }
+                return s;
         } else {
                 /* Caller must check execute permissions on the starting path component */
                 struct fd f = fdget_raw(nd->dfd);
@@ -2072,16 +2084,6 @@ static const char *path_init(struct nameidata *nd, unsigned flags)
                 fdput(f);
                 return s;
         }
-
-        nd->inode = nd->path.dentry->d_inode;
-        if (!(flags & LOOKUP_RCU))
-                return s;
-        if (likely(!read_seqcount_retry(&nd->path.dentry->d_seq, nd->seq)))
-                return s;
-        if (!(nd->flags & LOOKUP_ROOT))
-                nd->root.mnt = NULL;
-        rcu_read_unlock();
-        return ERR_PTR(-ECHILD);
 }
 
 static const char *trailing_symlink(struct nameidata *nd)